Category: Diseases and Disorders

EPM (Equine Protozoal Myeloencephalitis) is a moderately common neurological disease.

In the late 1980’s the parasitic organism was identified as Sarcocystis neurona and an antibody test was developed. Sarcoscystis falcutula has also been identified as potential cause of the condition and is less common.

Sarocystis neurona is now known to be present throughout the Western Hemisphere. The opossum has been determined to be a host within the cycle, with birds acting as intermediaries for the parasite. The incubation period for the disease is still unknown.

EPM affects different neurons throughout the neurological system and can result in dragging or spastic gaits. One side of the body may be affected, but not the other. If it affects the cranial nerves, the horse may have problems eating or drinking, have facial twisting, or undergo changes in the position of the eyes and ears.

Severely affected horses may become recumbent and have seizures.

Diagnosis of EPM is based upon finding antibodies or a DNA detection test from either blood or cerebrospinal fluid. There are still some challenges with accurate diagnosis.

A vaccine was developed, but has not been verified as effective at last report.

Biosecurity and Feed Security

It is very important to reduce the risk of horses consuming forage, water or feed that has been contaminated by opossums or any animals that may have consumed opossums.

Forage should be stored as securely as possible to minimize risk of contamination by fecal material and feeding management should be designed to reduce risk of contamination by opossums.

Pelleting and processing feed reduces/eliminates the risk of EPM transmission in feed or supplements. The feed should be securely stored in covered containers to prevent contamination on farm as contamination on the farm is a real risk.

To the degree possible, water sources should also be secure. A challenge with natural water sources!

Avoid having cat food or other food sources that attract opossums in the barn and stable areas.

Good biosecurity and sanitation are keys in reducing the risk of EPM for horses.

Ticks, horses, people and pets. The the last three are great, but what about those ticks? How could they be avoided or prevented from attaching. How to support prevention of the tick borne illnesses they cause for horses, humans and dogs? Most commonly, Lyme borreliosis or Lyme disease is among the most talked about tick borne illness. Lyme disease is characterized by symptoms caused from the spirochete bacteria Borrellia burdgorferi transmitted by the deer tick or Ixodes species.

In a horse, human or pet a tick bite area may appear hot, red, or inflamed. A horse may show symptoms of decreased activity, appear painful of lame, signs may also include kidney issues or no symptoms at all.

There are many sprays, tapes, ultrasonic devices, etc. on the market to try to prevent ticks from attaching. For horses and dogs, vaccine companies have created Lyme vaccinations. When administered at appropriate intervals animals are able to build an immune response to help in preventing an infection. There is no perfect vaccine and this is one step in prevention for this one major disease transmitted by ticks. Ticks are able to transmit other diseases such as piroplasmosis and ehrlichiosis to name a few additional diseases; preventing a tick bite is the first step.

What about an equine pre-purchase Lyme titer? In a study of Lyme titers performed in 2016, 33% are Lyme positive on the test with no clinical signs. The best method of prevention is avoiding ticks and avoiding tick bites.

Horse “fly-sprays” often contain permethrin, many homemade recipes have proven scientifically ineffective and should be used with caution. For humans it is recommended to treat clothing, foot wear with products containing 0.5% permethrin, stronger concentrations do not have more power, rather they will last longer over time on clothing. It is a good idea to use Environmental Protection Agency (EPA) registered repellents. Check your horse and yourself for ticks frequently and showering off after being outdoors. The mane, tail and flank are common places where ticks can attach on a horse. It is a myth that ticks are only found in long grasses, rather ticks can climb onboard a horse leg, lip, tail hair by resting on a short blade of grass and grasping on with its first pair of legs outstretched. Ticks do not discriminate as to which host they hop a ride for a good lunch, they will ride on a dog, horse or human and if the opportunity presents will transfer from one to the other and enjoy “dinner”.

To remove a tick use fine-tipped tweezers or a tick removal tool to grasp the tick as close to the skin’s surface as possible. Pull straight away from the skin, avoid twisting. Make sure the mouth parts are fully removed. Do NOT use a hot match, petroleum jelly or nail polish remover to try to remove a tick. This will cause the tick to regurgitate back into the host and can cause irritation to the skin. After removal clean area with soap and water or rubbing alcohol. After tick is removed, either stick them to sticky tape or place in a jar of rubbing alcohol. Tossing them onto the ground creates the opportunity for the tick to attach again or to another animal.

Ticks are able to survive in fairly cool conditions as well as fairly warm conditions. Heading into summer a myth is that once it is finally hot out the ticks are no longer out or once the weather cools ticks cannot survive. Ticks are amazing creatures at survival and can still grab on for a blood meal in some extreme temperatures.

Avoiding, preventing and checking for ticks is key in reducing the chances of a tick borne illness.

Weather and water conditions in many parts of the country have created or will create conditions favorable for the rapid growth of blue-green algae. Please be on alert with your horses, other animals and yourselves, and use precaution around water sources.

These single-celled organisms are actually algae-like bacteria instead of being true algae and are also referred to as Cyanobacteria. They grow rapidly and may produce the pea-soup green color in some bodies of water, along with some foul odors. The rapid growth periods, called “blooms” most frequently occur when there is a combination of warm weather, intermittent or limited rainfall and an accumulation of nutrients, particularly phosphorus and nitrogen. Blooms can range in color from green, to blue, brown or red. Water sources of fresh, brackish or salt water can all be affected by harmful algal blooms. Most often, slow moving water sources are the most suspect, although harmful algal blooms can occur in any water source with favorable conditions.

The planktonic groups produce the pea green water while the mat-forming groups produce dark mats that start on the bottom and float to the surface. The planktonic species (Anabena, Aphanizomenon and Microcystis) are believed to be most likely to produce toxins which can be harmful or fatal to animals when ingested. Although, you cannot tell by looking at the bloom whether or not cyanotoxins exist. (Fact Sheet on Toxic Blue-Green Algae, Purdue University, Carole A. Lembi)

Toxins may be ingested when animals drink the water, when they lick their coats after being in the water, or when they inhale water droplets. Animals are more likely to consume the water if fresh, clean water supplies are limited from other sources. Not all animals are deterred by foul odors that may be produced from the blooms. Animals that drink or have exposure to the water during a period when cyanotoxins are being produced may be affected, but toxins are not always produced when there is a bloom.

Providing a source of fresh, clean, safe drinking water is the best way to avoid causing animals to consume questionable water. If animals go swimming, they should be cleaned off before they have a chance to lick their coats, try not to engage in physical exertion near the water supply where inhaling water droplets could occur.

Preventing access to waterways is one way to prevent toxin exposure. Swimming in, contact with, breathing in water droplets or drinking water in ponds/lakes/streams is not recommended during temperatures or conditions that are favorable for blooms to exist. Most often slow moving water or calm water that has a greenish appearance are those most suspect to algal blooms, however they can exist an any water source if the conditions have been favorable. If contact has occurred watch for symptoms and promptly notify your veterinarian. When in doubt keep your animals and yourselves out of the water. Provide access to fresh, clean water at all times for your animals.

Toxic symptoms may include:

Diarrhea

Vomiting

Rash and skin irritation

Difficulty breathing

Seizure

Death

While not all “blooms” may produce toxins, avoiding exposure to or consumption of suspect water is recommended. Risks of illness after the blooms are gone are low, however some toxins can still remain in the water once the blooms are gone. More information is available from local and state pollution control sites or extension sites. Health Departments recommend, when in doubt, keep out of the water.

Preventing run-off of nutrients into ponds and lakes is also important to help reduce the risk of these algae blooms. Keeping vegetation around water sources can help naturally filter. Drought conditions in some areas have also increased the concentration of nutrients in the remaining water in ponds, lakes and streams.

Ticks can transmit a number of disease-causing organisms to horses, including Lyme disease. Lyme disease is caused by the bacterium Borrelia burgdorferi. Many horses are exposed to this organism through tick bites, but few develop clinical illness, usually months post tick bite.

As in dogs and people, the possible diagnosis of Lyme disease often arises when more common causes of lameness, joint swelling, kidney disease, moon blindness or incoordination have been ruled out.

Typically, two blood samples are taken 2 to 3 weeks apart to see if anti-Borrelia antibody levels have changed significantly to indicate active infection. The two samples are important because many normal horses may carry high antibody levels. The disease can also be diagnosed by finding the organism in tissue taken by biopsy from an affected joint or lymph node. The SNAP test kits utilized for testing dogs for Lyme disease are likely valid for use in the horse, but so far are not licensed for that purpose.

If evidence of Lyme disease is found, a veterinarian may try a course of antibiotics to see if this will improve the horse’s clinical abnormalities. There are currently no Lyme vaccines approved for use in the horse.

Horse owners need to be tick-vigilant and manage their horses’ environment to reduce tick habitat. Clearing brush out of pastures and along both sides of fence lines is recommended. Keeping pastures mowed may also be helpful. Before riding through long grass or brush, use of topical insecticides is highly recommended.

A characteristic that is often times difficult to pin-point, self-mutilation is sometimes an overlooked concern.

The challenge lies in determining whether it’s truly a self-mutilation concern, or a behavior caused by colic or other health concerns.

So what is self-mutilation in horses? Generally, it’s much more common in males (often stallions) than in females.

The pattern can develop as a colt, where they may begin to nip at their chest or flank. It is often brought by the on-set of sexual maturity. It can start as missing patches in the hair coat, and progress to more prevalent wounds.

It is important, if your horse is displaying signs of self-mutilation, to consult your veterinarian to rule out internal or external sources of pain.

This can often times be the reason for the self-mutilation, so it’s important to troubleshoot these issues with your veterinarian.

Eliminating the pain (if present) is the first step in combating the problem. Other options could include a ridged neck cradle, providing more time out of confinement, adding a stall-mate or increasing work or exercise.

Like with cribbing, feed management can also play a factor. Providing free-choice hay, with a slow feeding haynet can sometimes ease that boredom that can be associated with the cause of self-mutilation.

Again, consult your veterinarian on a treatment plan that will best fit you and your horse.

I’ve often heard, ‘my horse has a hay belly, what should I do differently?’ Or,” he’s really big in the belly but he doesn’t have good muscles.” Apart from a broodmare belly, post-colic surgery effects or a parasite situation, the answer sounds like a nutritional imbalance. The good news is, once you know what a nutritional imbalanced hay belly is and what causes it, you can make adjustments in your program and avoid it in the future.

What does it look like?

Willow has had 4 foals, and as a result, tends to show characteristics of a hay belly.

Have you ever seen a young or growing horse with a big belly while the rest of their body looks small? Or a mature horse that has a midsection that hangs low, while ribs are visible and muscles along the back and hindquarter are hard to find? How about the ‘pregnant gelding’ situation? All of these are describing a hay belly. On a regular basis, you should conduct a body condition score on your horse to check for muscle mass as well as appropriate fat deposition in key areas. It’s important to check all areas indicated, since a rib or belly check alone doesn’t provide all the information.

What causes it?

When too many low-value calories are consumed without adequate protein (including essential amino acids), the body stores the calories as energy in cells yet the needed protein isn’t available to maintain muscle mass. In the absence of adequate protein, muscles atrophy while stored energy increases. Over time, a hay belly emerges as muscle mass over the top is lost and gut size may expand.

The biggest factor is overfeeding fiber high in Neutral Detergent Fiber (NDF) while under feeding adequate levels of quality protein. NDF is a measurement of cell wall content in plants such as grasses. As the plant matures, it builds up stronger cell walls so that it may hold itself upright. The stronger these walls, the less digestible these cells are for a horse. So when fed very mature hay, your horse is less able to digest that hay, as compared to hay with a lower NDF value (less mature). In addition to being higher in NDF, the grasses also tend to be lower in the quality proteins; important nutrients for developing and maintaining muscles.

How to prevent a hay belly

First, feed the best quality hay that you can find in the correct amount for your horse’s body weight, age and activity level. The hay that is smooth and ‘leafy’ tends to have levels of NDF that are better for the horse to digest. Hay that is pointy to the touch or looks like it’s a green version of straw should be avoided as it simply offers little nutritional value for the horse.

How do I get rid of a hay belly if my horse has one?

First, check the quality and quantity of hay your horse is eating. If the quality is adequate, then it’s time to reevaluate the quantity fed. A horse should be fed 1.0-1.75 pounds/100 pounds of body weight of hay per day. Not a fan of math? Yea, me neither. Here’s a quick answer: for a horse weighing 1,000 pounds, that would be between 10-17.5 pounds of hay each day, ideally divided into 2 or even 3 feedings. Check to be sure you’re not inadvertently overfeeding, or underfeeding if your horse is actually bigger than 1,000 lbs. Learn to estimate your horse’s weight accurately here.

The last piece of the puzzle is feed. Make sure that the concentrate you provide is offering adequate quality protein. Total protein alone can’t support or develop ideal muscles. The right balance of amino acids is needed to build and maintain muscle quantity and quality. Look for feeds that guarantee levels of Lysine, Methionine and Threonine. These three key amino acids are the most important for your horse. And lastly, check to be sure you’re feeding the appropriate amount of concentrate. Feeding a balanced diet and adding some exercise to help develop muscle mass and tighten up that tummy is a great way to reclaim that belly!

If you’ve walked by your horses feeding area or water trough and noticed slimy balls of half chewed food laying on the ground, your horse may be quidding. Quidding is a response to mouth pain in which the horse loses or spits balls of semi-chewed food stuffs out of their mouth.

The most common cause of quidding is teeth that are uneven or that have sharp points. This does not allow the mouth to close properly and makes chewing extremely difficult. There is a host of other mouth issues that can lead to this problem as well, including cavities, abscesses, and unseen injuries. This problem most commonly occurs in older horses, however all ages can be affected.

Besides the fact that quidding is an indicator that there is something wrong (and probably painful) in your horse’s mouth, this is an issue for a very simple reason: if the feed is falling on the ground, it is not being ingested and used by your horse. This can result in loss of weight and body condition as the horse may only swallow a fraction of what is being fed. In fact, one of the first things you should check if your horse starts dropping weight and losing body condition is the condition of the teeth and mouth.

The good news is that quidding can be greatly improved or even cured all together with regular dental care by your veterinarian or an equine dentist. Often a process called floating the teeth can help file down sharp or uneven places on the teeth. Dental exams should happen at a minimum of once per year, even on healthy horses with no known problems. For horses who have dental issues, the check ups and/or treatments may be prescribed more often.

In addition to regular dental exams, a horse with dental issues should be fed a feed that is easy to chew and digest. Make sure the ration is nutrient-dense to make the most out of what they do take in and, if necessary, consider switching the horse with severe dental problems over to a complete feed that may be soaked to soften before feeding.

My horse is a hard keeper, and is also prone to ulcers. What should I feed?

Horses vary a great deal in what level of nutrition is required to maintain desired body condition and muscle mass. Horses have not been selected or bred based on feed efficiency, feed conversion or rate of gain, so there a lot of variation between horses.

A horse that is a hard keeper may require more Calories per day to maintain body condition than an easy keeper doing the same work. One way to help this horse will be to feed high quality forage that has a high Relative Feed Value (RFV) that is associated with higher Digestible Energy (DE) per pound. A good choice might be an alfalfa or alfalfa grass mix that was cut at early maturity so it has fine stems and lots of leaves. This hay could be fed free choice or at least 3-4 times per day at a rate of about 2% or above BW/head/day.

The hard keeper may also benefit from a commercial feed that is high fat (8-9 % or higher) and controlled starch and sugar (so it can be fed at higher levels) with amino acid fortification (lysine, methionine and threonine) to help maintain muscle mass. This feed can be fed a minimum of 2 times per day, and preferably 3-4 times per day so that the quantity being fed can be increased while controlling risk of starch overload through smaller individual meals. The quantity can be increased with the desired forage to produce weight gain, and then adjusted to maintain desired weight.

This feeding plan may also be useful in reducing the risk of having ulcers redevelop after a horse has been treated with appropriate medication. Free choice forage or pasture is a good option so the horse’s stomach is not empty for long periods of time. Alfalfa contains levels of calcium and magnesium that may be useful in buffering acid in the stomach. High fat, controlled starch feeds fed in small meals at frequent intervals may also be useful in reducing the risk of re-occurrence. A feed that contains specific metal amino acid complex trace minerals may also help improve gut health and digestive tract tissue integrity in the stomach.

Cribbing, the process of a horse biting down on a stationary wooden structure, applying pressure and then breathing in deeply, can be destructive to more than just your barn and stalls!

A wooden fence that has been chewed by a cribber.

While cribbing has traditionally been thought to be just a vice or bad habit, new information indicates that a horse that cribs may be responding to a digestive upset. The act of cribbing produces excess saliva. This saliva helps to buffer the stomach and can calm the pain of things like ulcers and other digestive problems.

If you have a horse that cribs, the first step should be determining why the problem started. This may very well include a trip to the vet to rule out gastric ulcers or digestive issues. In cribbers who are diagnosed with ulcers, the behavior often stops or is reduced when treatment for the ulcers is started. Cribbing can also be caused by extreme boredom and is usually associated with horses who spend most of their time in stall situations.

It is important to note that cribbing is not a learned behavior – horses don’t start cribbing because they see their stablemates doing it. Rather, in a group of horses that all begin to crib the catalyst may be management practices that lead to some type of gastric distress. Some of these practices that can lead to cribbing include:

The bad news is that once a horse has started cribbing, it can be a hard habit to break. As the horse bites down on the wood and inhales, endorphins are released that can give the animal a “high”. That is why it can be very difficult for the horse that has started cribbing to stop – they get addicted to what it does to their body. Unfortunately, cribbing is a very good way to cause colic (as well as destroy property), so all possible steps should be taken to end the behavior.

Once the source of the cribbing is confirmed and addressed, some recommendations to help stop the behavior and break the addiction can include:

Adequate long stemmed forage provided throughout the day

Plenty of turn out time with opportunities to interact with other horses

Stall toys to help ease boredom

Placing feed in multiple locations around the pen to make the horse mimic his natural grazing behavior

Feeding grain meals in small amounts several times per day rather than all at once

Providing a balanced diet

Giving ample access to loose white salt

Using a special cribbing collar or strap

Covering wooden surfaces with anti-chew paint

Treating the cribbing horse can be a challenge, but remember that the first step is figuring out why the problem started. Your horse’s cribbing may just be his way of telling you that he is in pain and needs your help.

In my previous blog post on this topic, we explored the role starch plays in the horse’s diet. After (hopefully) warming you up to the idea of how useful this nutrient can be, I’d like to now dig in to how you can compare and contrast the varying levels of starch (and sugar*) in feeds and hopefully this information will help you compare and contrast to choose the best option for your horse.

Contrary to what you may have been told or read, most horses can tolerate a moderate level of starch each day. If you have a horse that has been diagnosed with a form of equine metabolic disease, you will need to limit your horse to a ‘low’ controlled starch and sugar diet….which includes forage (hay and pasture). Fructans, the sugars in forages, are too often overlooked when assessing the total diet of an EMS horse.

Even if your horse has not been diagnosed with EMS, it is still important to understand the starch level in his diet and take it into consideration for your overall program. Think you know how to compare starch levels from one feed to another? You might be surprised to find out that a bit of math is required. Simply comparing the percentage of starch on feed tags doesn’t quite tell the whole story. To get to a true comparison, it is important to factor in the recommended feeding rate, which is, after all, what the horse experiences.

Let’s compare two feeds that are marketed as ‘low starch’; one has a starch maximum guarantee of 7% while the other has a maximum of 11%. Pretty easy to tell which one is the lowest, right?

Look beyond the percentage to find what's really in the feed

Not quite. For our example, let’s say we have a 1,000 pound horse at maintenance level activity. Feed A, with 7% starch is recommended to be fed at a rate of 6 pounds per day, meanwhile, Feed B has a starch maximum of 11% and is recommended to be fed at a rate of 2.5 pounds per day.

Wow – a big surprise! Not only is the 11% starch feed actually lower in grams of starch per day than the 7% product, the difference is actually rather significant given how different the percentages were. It is important to keep in mind that it all comes down to what your horse actually ingests, so understanding the recommended feeding rate in pounds and then weighing your feed to hit that mark is what will make the difference.

It’s also important to understand that horses who do not experience a form of EMS have a higher tolerance for starches and sugar in their diet…and in fact, the performance horse will actually need those nutrients to support their activity levels. It all comes to down to understanding what’s in your feed and how much you’re giving them.

*Though this blog article addresses ‘starch’ the same principles apply to determining the amount of other nutrients in a feed.